Who can I call to have a payphone installed at my place of business?
Public telephones are no longer owned by the large telecom entities. Verizon, AT&T, Sprint, and other such companies abandoned their payphone customers some years ago, leaving what’s left of the business to smaller concerns.
Nationwide the largest PSP (Payphone Service Provider) is PTS (Pacific Telemanagement Services), which also does business as Jaroth, Inc.
At the Payphone Project you will find a page linking to the FCC’s database of Payphone Service Providers Currently In Business throughout the United States. The FCC’s listings are not necessarily comprehensive, so you might have to do some additional research before finding a PSP that is right for your needs.